Light emitting device and light emitting device package having the same

ABSTRACT

Disclosed are a light emitting device and a light emitting device package having the same. The light emitting device includes a light emitting structure including a first conductive type semiconductor layer, a second conductive type semiconductor layer, and an active layer between the first conductive type semiconductor layer and the second conductive type semiconductor layer, wherein the first conductive type semiconductor layer includes a stepped structure having a second top surface stepped lower than the first top surface thereof; an insulating layer disposed on a lateral surface of the light emitting structure and the second top surface of the first conductive type semiconductor layer; an electrode electrically connected with the first conductive type semiconductor layer; an electrode layer under the second conductive type semiconductor layer; and a protective layer disposed on a periphery portion of a lower surface of the second conductive type semiconductor layer.

The present application claims priority under 35 U.S.C. §119(a) ofKorean Patent Application No. 10-2010-0012758 filed on Feb. 11, 2010.

BACKGROUND

The embodiment relates to a light emitting device and a light emittingdevice package having the same.

Groups III-V nitride semiconductors have been extensively used as mainmaterials for light emitting devices, such as a light emitting diode(LED) or a laser diode (LD), due to the physical and chemicalcharacteristics thereof. In general, the groups III-V nitridesemiconductors include a semiconductor material having a compositionalformula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, and 0≦x+y≦1).

The LED is a semiconductor device, which transmits/receives signals byconverting an electric signal into infrared ray or light using thecharacteristics of compound semiconductors. The LED is also used as alight source.

The LED or the LD using the nitride semiconductor material is mainlyused for the light emitting device to provide the light. For instance,the LED or the LD is used as a light source for various products, suchas a keypad light emitting part of a cellular phone, an electricsignboard, and an illumination device.

SUMMARY

The embodiment provides a light emitting device and a light emittingpackage, capable of preventing a compound semiconductor layer from beingdamaged according to a substrate separating process.

The embodiment provides a light emitting device and a light emittingdevice package having the same, in which a first conductive typesemiconductor layer has a stepped structure.

According to the embodiment, the light emitting device includes a lightemitting structure including a first conductive type semiconductorlayer, a second conductive type semiconductor layer, and an active layerbetween the first conductive type semiconductor layer and the secondconductive type semiconductor layer, wherein the first conductive typesemiconductor layer includes a stepped structure having a second topsurface stepped lower than the first top surface thereof; an insulatinglayer disposed on a lateral surface of the light emitting structure andthe second top surface of the first conductive type semiconductor layer;an electrode electrically connected with the first conductive typesemiconductor layer; an electrode layer under the second conductive typesemiconductor layer; and a protective layer disposed on a peripheryportion of a lower surface of the second conductive type semiconductorlayer.

-   -   According to the embodiment, the light emitting device includes        a light emitting structure including a first conductive type        semiconductor layer having a stepped structure, a second        conductive type semiconductor layer, and an active layer between        the first conductive type semiconductor layer and the second        conductive type semiconductor layer; an insulating layer        disposed on an peripheral portion of the light emitting        structure; an electrode electrically connected with the first        conductive type semiconductor layer; an electrode layer        including an ohmic layer under the second conductive type        semiconductor layer; and a protective layer formed around a        lower surface of the second conductive type semiconductor layer,        wherein the stepped structure of the first conductive type        semiconductor layer includes a first recess portion between a        first lateral surface and the electrode, a second recess portion        between a second lateral surface and the electrode, and a third        recess portion connected to the first recess portion and the        second recess portion.    -   According to the embodiment, a method of manufacturing the light        emitting device, the method comprising: forming an absorption        layer at a peripheral portion of a top surface of a substrate,        wherein the absorption layer includes a material having a band        gap energy lower than that of the substrate; forming a light        emitting structure including a first conductive type        semiconductor layer, an active layer, and a second conductive        type semiconductor layer on a first substrate and the absorption        layer; forming a protective layer at an outer peripheral portion        of a top surface of the light emitting structure; forming an        electrode layer on the light emitting structure; forming a        conductive support member on the electrode layer; removing the        substrate from the light emitting structure; removing the        absorption layer; and forming an electrode on the first        conductive type semiconductor layer.

According to the embodiment, a light emitting device package includes abody, a plurality of lead electrodes on the body, a light emittingdevice provided on at least one of the lead electrodes, and electricallyconnected with the lead electrodes, and a molding member on the lightemitting device. The light emitting device includes a light emittingstructure including a first conductive type semiconductor layer, asecond conductive type semiconductor layer, and an active layer betweenthe first conductive type semiconductor layer and the second conductivetype semiconductor layer, wherein the first conductive typesemiconductor layer includes a stepped structure having a second topsurface stepped lower than the first top surface thereof; an insulatinglayer disposed on a lateral surface of the light emitting structure andthe second top surface of the first conductive type semiconductor layer;an electrode electrically connected with the first conductive typesemiconductor layer; an electrode layer under the second conductive typesemiconductor layer; and a protective layer disposed on a peripheryportion of a lower surface of the second conductive type semiconductorlayer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view showing a light emitting deviceaccording to a first embodiment;

FIG. 2 is a plan view of FIG. 1;

FIGS. 3 to 13 are sectional views showing the light emitting device ofFIG. 1;

FIG. 14 is a side sectional view showing a light emitting deviceaccording to a second embodiment;

FIG. 15 is a side sectional view showing a light emitting deviceaccording to a third embodiment;

FIGS. 16 and 17 are sectional views showing a method of manufacturing alight emitting device according to a fourth embodiment;

FIGS. 18 and 19 are a sectional view showing a method of manufacturingof a light emitting device according to a fifth embodiment;

FIG. 20 is a side sectional view showing a light emitting device packageaccording to an embodiment;

FIG. 21 is a disassembled perspective view of a display apparatusprovided with the light emitting device package of FIG. 20;

FIG. 22 is a schematic sectional view illustrating another example of adisplay apparatus provided with the light emitting device package ofFIG. 20; and

FIG. 23 is a perspective view of a lighting apparatus provided with thelight emitting device package of FIG. 20.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the description of the embodiments, it will be understood that, whena layer (or film), a region, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another region, another pad, or another pattern, it can be “directly” or“indirectly” on the other substrate, layer (or film), region, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

Hereinafter, the embodiments will be described with reference to theaccompanying drawings. The thickness and size of each layer shown in thedrawings may be exaggerated, omitted or schematically drawn for thepurpose of convenience or clarity. In addition, the size of elementsdoes not utterly reflect an actual size.

FIG. 1 is a side sectional view showing a light emitting device 100according to a first embodiment, and FIG. 2 is a plan view of FIG. 1.

Referring to FIGS. 1 and 2, the light emitting device 100 includes anelectrode 115, a light emitting structure 135 having a plurality ofcompound semiconductor layers 110, 120, and 130, a protective layer 140,an electrode layer 150, an adhesion layer 160, a conductive supportmember 170, and an insulating layer 180.

The light emitting device 100 may include compound semiconductors suchas light emitting diodes (LEDs) including compound semiconductors ofgroup III-V elements. The groups III-V nitride semiconductors include asemiconductor material having a compositional formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, and 0≦x+y≦1). The LEDs may bevisible-ray band LEDs to emit blue, green, red light or UV LEDs, but theembodiment is not limited thereto.

The light emitting structure 135 includes the first conductive typesemiconductor layer 110, the active layer 120, and the second conductivetype semiconductor layer 130 that include compound semiconductors ofgroup III-V elements.

The first conductive type semiconductor layer 110 may include oneselected from the group consisting of GaN, AlN, AlGaN, InGaN, InN,InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, which are compoundsemiconductors of III-V group elements doped with a first conductivedopant. When the first conductive type semiconductor layer 110 is an Ntype semiconductor layer, the first conductive dopant includes an N typedopant such as Si, Ge, Sn, Se or Te. The first conductive typesemiconductor layer 110 may have a single layer or a multilayer, but theembodiment is not limited thereto. The first conductive typesemiconductor layer 110 is provided on a top surface thereof withroughness and/or a pattern, but the embodiment is not limited thereto.

Referring to FIGS. 1 and 2, the first conductive type semiconductorlayer 110 is provided at edges thereof with a stepped structure 104, andthe stepped structure 104 includes a second top surface S2 stepped lowerthan the first top surface S1 of the first conductive type semiconductorlayer 110. The stepped structure 104 is formed along the edges of thefirst conductive type semiconductor layer 110. The stepped structure 104has a first recess portion between a first lateral surface of the firstconductive type semiconductor layer 110 and the electrode 115, a secondrecess portion between a second lateral surface of the first conductivetype semiconductor layer 110 and the electrode 115, and plurality ofthird recess portions connected to the first recess portion and thesecond recess portion. For example, when viewed in a plan view, thestepped structure 104 may have a loop shape such as ring shape, a frameshape, or a strip shape. The stepped structure 104 may have a polygonalshape such as a rectangle or may have a hemispherical side section.

The stepped structure 104 may have at least two open sides. The secondtop surface S2 of the stepped structure 104 may be lower than the firsttop surface S1 of the first conductive type semiconductor layer 110. Thedepth of the stepped structure 104 may be thinner than the thickness ofthe first conductive type semiconductor layer 110.

The light emitting device 100 is provided at an outer portion thereofwith the insulating layer 180, and the insulating layer 180 extends tothe top surface S2 of the first conductive type semiconductor layer 110.

The insulating layer 180 is formed in the stepped structure 104. Thatis, the insulating layer 180 may be formed in a stepped structure at thestepped structure 104. Since the stepped structure 104 includes thesecond top surface S2 of the first conductive type semiconductor layer110 and a lateral surface between the first top surface S1 and thesecond top surface S2, light can be emitted through the surface of thestepped structure 104. This can improve light extraction efficiency andthe distribution of optical orientation angles

An interval T1 between the stepped structures 104 on the firstconductive type semiconductor layer 110 is an interval between thesecond top surface S2 provided at one side of the first conductive typesemiconductor layer 110 and the second top surface S2 provided at anopposite side of the first conductive type semiconductor layer 110. Theinterval T1 may correspond to an interval between laser shots,substantially, the size of one laser shot. The first conductive typesemiconductor layer 110 may include an upper layer having a first widthand a lower layer having a second width narrower than the first width.

In the stepped structure 104, the width of the second top surface S2 maybe greater than a width of an overlap region of edges of adjacent lasershots. In this case, a laser beam is irradiated into a growth substrateof a semiconductor layer. In detail, the laser beam may be irradiatedinto the growth substrate with the size of a shot having a predeterminedarea. According to the size of the shot, the interval between thestepped structures 104 or the width of the stepped structure 104 may bechanged.

The first conductive type semiconductor layer 110 may be providedthereon with the electrode 115. The electrode 115 may be a pad or anelectrode having a branch or arm structure connected to the pad, but theembodiment is not limited thereto.

The electrode 115 makes ohmic contact with the top surface of the firstconductive type semiconductor layer 110. The electrode 115 may includeone of Cr, Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag, Cu and Au or themixture of plural materials in a single layer or in a multiple layer.The electrode 115 may be formed in consideration of an ohmic propertywith the first conductive type semiconductor layer 110, an adhesionproperty between metallic layers, a reflective property, andconductivity.

The active layer 120 is provided under the first conductive typesemiconductor layer 110. The active layer 120 may have a single quantumwell structure, a multiple quantum well structure, a quantum wirestructure, or a quantum dot structure. The active layer 120 may have astack structure including a well layer and a barrier layer, which aremade from compound semiconductors of group III-V elements. For example,the active layer 120 may have a stack structure of an InGaN welllayer/GaN barrier layer, an InGaN well layer/AlGaN barrier layer, or anInGaN well layer/InGaN layer. The band gap of the barrier layer may behigher than the band gap of the well layer.

A conductive clad layer may be formed on and/or under the active layer120. The conductive clad layer may include a nitride-basedsemiconductor. The band gap of the conductive clad layer may be higherthan the band gap of the barrier layer.

The second conductive type semiconductor layer 130 is disposed under theactive layer 120. The second conductive type semiconductor layer 130includes the compound semiconductors of group III-V elements doped withthe second conductive dopant. For instance, the second conductive typesemiconductor layer 130 may include at least one selected from the groupconsisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP,GaAs, GaAsP, and AlGaInP. If the second conductive type semiconductorlayer is a P type semiconductor layer, the second conductive dopantincludes the P type dopant such as Mg or Ze. The second conductive typesemiconductor layer 130 can be prepared as a single layer or a multiplelayer, but the embodiment is not limited thereto.

The light emitting structure 135 may further include a third conductivetype semiconductor layer under the second conductive type semiconductorlayer 130. The third conductive type semiconductor layer may havepolarities opposite to those of the second conductive type semiconductorlayer 130. The first conductive type semiconductor layer 110 may includea P-type semiconductor layer, and the second conductive typesemiconductor layer 130 may include an N-type semiconductor.Accordingly, the light emitting structure 135 may include at least oneof an N-P junction structure, a P-N junction structure, an N-P-Njunction structure, and a P-N-P junction structure.

The protective layer 140 and the electrode layer 150 are formed underthe second conductive type semiconductor layer 130 or the thirdconductive type semiconductor layer. Hereinafter, for the purpose ofexplanation, the second conductive type semiconductor layer 130 willserve as the lowest layer of the light emitting structure 135.

The electrode layer 150 is provided at an inner portion of a lowersurface of the second conductive type semiconductor layer 130, and theprotective layer 140 is provided at a peripheral portion of the lowersurface of the second conductive type semiconductor layer 130. Theprotective layer 140 is defined as a channel layer of the light emittingdevice.

The protective layer 140 may be exposed at a channel region M1 outsideof a chip, or may be provided under the insulating layer 180. Thechannel region M1 in which the protective layer 140 is providedcorresponds to a boundary region of chips, that is, a peripheral regionof a device. An inner portion of a top surface of the protective layer140 makes contact with the lower surface of the second conductive typesemiconductor layer 130 with a predetermined width (e.g., width of a fewmicrometers (μm) or a few tens micrometers (μm). The width variesdepending on a chip size. The protective layer 140 may have a thicknessof about 0.02 μm to about 5 μm, and the thickness may vary depending onthe chip size.

Referring to FIGS. 1 and 2, the protective layer 140 may be formedaround the lower surface of the second conductive type semiconductorlayer 130. When viewed in a plan view of a device, the protective layer140 may have a loop-shape pattern, a ring-shape pattern, or aframe-shape pattern. The protective layer 140 may have a continuouspattern or a discontinuous pattern.

The protective layer 140 may include a material (e.g., a transmissiveoxide, a transmissive nitride, or a transmissive insulating material)having a refractive index lower than that of compound semiconductors ofgroup III-V elements. The protective layer 140 may include one selectedfrom the group consisting of indium tin oxide (ITO), indium zinc oxide(IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO),indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO),aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide(GZO), SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃, and TiO₂.

The protective layer 140 can prevent the light emitting structure 135from being shorted even if the outer wall of the light emittingstructure is exposed to moisture, thereby enabling the LED to havesuperior property under the high moisture condition. If the protectivelayer 140 includes a transmissive material, when the laser scribingprocess is performed, the laser beam passes through the protective layer140 so that metallic particles caused by the laser beam may not begenerated from the channel region M1, thereby preventing interlayershort from occurring at the sidewall of the light emitting structure.

The protective layer 140 spaces the outer wall of each layer 110, 120,or 130 of the light emitting structure 135 apart from the electrodelayer 150.

The electrode layer 150 may be provided under the second conductive typesemiconductor layer 130, and may include at least one of an ohmic layer,an electrode layer, and adhesion layer. The electrode layer 150 may havea single layer structure or a multiple-layer structure. The ohmic layermay be prepared in the form of a layer or a plurality of patterns. Theohmic layer may include at least one of a metallic material or an oxidematerial. For example, the ohmic layer may include at least one selectedfrom the group consisting of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO,GZO, IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au, Ni/IrOx/Au/ITO, Pt, Ni, Au, Rh,and Pd. The reflective layer may be prepared in the structure of atleast one layer including Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au,Hf, and alloy thereof. The electrode layer 150 may include seed metal,and the seed metal is used for a plating process. Accordingly, theelectrode layer 150 may selectively an ohmic layer, a seed layer, or anelectrode layer, but the embodiment is not limited thereto.

The electrode layer 150 may cover an entire portion of a lower surfaceof the protective layer 140, or 80% or less of a width of the lowersurface of the protective layer 140.

Since the width of the electrode layer 150 is greater than the width ofthe light emitting structure 135, the reflection efficiency of lightincident onto the electrode layer 150 can be improved. Accordingly, thelight extraction efficiency can be improved.

The electrode layer 150 may make contact with a portion or an entireportion of the protective layer 140 under the protective layer 140, butthe embodiment is not limited thereto.

The adhesion layer 160 may be provided under the electrode layer 150,and may make contact with the lower surface of the protective layer 140according to the structure of the electrode layer 150, but theembodiment is not limited thereto. The adhesion layer 160 may includebarrier metal or bonding metal. For example, the adhesion layer 160 mayinclude at least one selected from the group consisting of Ti, Au, Sn,Ni, Cr, Ga, In, Bi, Cu, Ag and Ta.

The adhesion layer 160 may serve as a bonding layer, and is bonded withthe conductive support member 170 provided under the adhesion layer 160.The conductive support member 170 can be plated on the electrode layer150 or attached to the electrode layer 150 in the form of a sheetwithout using the adhesion layer 160.

The adhesion layer 160 is provided under with the conductive supportmember 170, and the conductive support member 170 serves as a basesubstrate. The conductive support member 170 may include copper (Cu),gold (Au), nickel (Ni), molybdenum (Mo), copper-tungsten (Cu—W), or acarrier wafer such as Si, Ge, GaAs, ZnO, SiC, SiGe, or GaN. Theconductive support member 170 may not be formed, or may include aconductive sheet.

The insulating layer 180 may be formed at the outer portion of the lightemitting structure 135. In detail, the insulating layer 180 may beformed on the top surface of the first conductive type semiconductorlayer 110 and at a later surface of each layer 110, 120, or 130 of thelight emitting structure 135. The insulating layer 180 may extend to thetop surface of the protective layer 140. The insulating layer 140 mayinclude a material, such as SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃,or TiO₂, having a refractive index lower than a refractive index (GaN:about 2.4) of the compound semiconductor.

FIGS. 3 to 13 are sectional views showing a method of manufacturing thelight emitting device of FIG. 1.

Referring to FIGS. 3 and 4, a substrate 101 is loaded into growthequipment and compound semiconductors of group II to VI elements areformed on the substrate 101 in the form of a layer or a pattern.

The growth equipment may be selected from the group consisting of E-beamevaporator, PVD (physical vapor deposition), CVD (chemical vapordeposition), PLD (plasma laser deposition), dual-type thermalevaporator, sputtering, and MOCVD (metal organic chemical vapordeposition). However, the embodiment is not limited to the above growthequipment.

The substrate 101 may include one selected from the group consisting ofAl₂O₃, GaN, SiC, ZnO, Si, GaP, InP, Ga₂0₃, conductive material and GaAs.A concave-convex pattern can be formed on the top surface of thesubstrate 101.

An absorption layer 105 may be formed at a peripheral portion of a topsurface of the substrate 101. The absorption layer 105 may be formedthrough a sputtering or deposition scheme using a mask pattern. Theabove process may be changed in the technical scope of the embodiment.The absorption layer 105 has a thickness of about 100□ to about 30000□or more. The absorption layer 105 may have a thickness less than athickness of a GaN thin film, for example, the thickness of the firstconductive type semiconductor layer 110. The absorption layer 105 mayhave a width of about 10 μm to about 30 μm.

The absorption layer 105 includes a material enduring at an epitaxialgrowth temperature. In addition, since the absorption layer 105 mayinclude a material having a band gap energy lower than energy of a laserwavelength used when the substrate 101 is removed, the absorption layer105 may include absorb light having the laser wavelength.

In addition, the absorption layer 105 includes a material having athermal expansion coefficient lower than those of the substrate 101 anda compound semiconductor (e.g., GaN), thereby mitigating stress causedby the difference of the thermal expansion coefficient when the compoundsemiconductor is grown. When the absorption layer 105 includes ZnO, thesubstrate 101 includes sapphire, and the nitride semiconductor includesGaN, the thermal expansion coefficient of the ZnO is about 2.9×10⁻⁶/K,the thermal expansion coefficient of the sapphire is about 7×10⁻⁶/K, andthe thermal expansion coefficient of the GaN is about 5.6×10⁻⁶/K, butthe embodiment is not limited to the above numeric values of the thermalexpansion coefficients.

The absorption layer 105 may include a metallic oxide or a metallicnitride. The absorption layer 105 may have a single layer structure or amultiple layer structure including ZnO, WO, and MoO.

The ZnO, WO, or MoO endure a high temperature (i.e., epitaxial growthtemperature), and may have a band gap of about 3.3 eV. When thesubstrate 101 includes sapphire, the band gap of the substrate 101 isabout 9.9 eV, and the band gap of GaN is about 4 eV to about 5 eV. Theabsorption layer 105 may include a material of TiO₂, SiO₂, Si₃N₄, TiN,AlN, GaN, W, or Mo, but the embodiment is not limited thereto.

The absorption layer 105 may be formed at one shot interval T1 of alaser beam. When viewed in a plan view, the absorption layer 105 mayhave a continuous structure in at least one of a ring shape, a stripshape, and a frame shape. The absorption layer 105 may have a widthgreater than that of an overlap area of one laser shot and a next lasershot.

Referring to FIG. 5, the substrate 101 is provided thereon with a layeror a pattern including compound semiconductors of group II to VIelements. For example, the substrate 101 may include at least one of aZnO layer (not shown), a buffer layer (not shown), and an undopedsemiconductor layer (not shown).

The buffer layer and the undoped semiconductor layer may include acompound semiconductor of group III-V elements. The buffer layer reducesa lattice constant difference from the substrate 101, and the undopedsemiconductor layer may include an undoped GaN-based semiconductorlayer. Hereinafter, a structure in which the first conductive typesemiconductor layer 110 is formed on the substrate 101 will be describedas one example for the purpose of explanation.

The first conductive type semiconductor layer 110 is formed on thesubstrate 101, and the active layer 120 is formed on the firstconductive type semiconductor layer 110. The second conductive typesemiconductor layer 130 is formed on the active layer 120.

The first conductive type semiconductor layer 110 may include oneselected from the group consisting of GaN, AlN, AlGaN, InGaN, InN,InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP, which arecompound semiconductors of III-V group elements doped with a firstconductive dopant. When the first conductive type semiconductor layer110 is an N type semiconductor layer, the first conductive dopantincludes an N type dopant such as Si, Ge, Sn, Se or Te. The firstconductive type semiconductor layer 110 may have a single layer or amultilayer, but the embodiment is not limited thereto.

The first conductive type semiconductor layer 110 may be formed on thesubstrate 101 and the absorption layer 105. When the first conductivetype semiconductor layer 110 is grown from the absorption layer 105, thefirst conductive type semiconductor layer 110 may seal the absorptionlayer 105. For example, the first conductive type semiconductor layer110 may be grown in the form of a flat top surface by adjustingpressure, a temperature, and gas flow rate, but the embodiment is notlimited thereto.

In this case, first stress P1 is generated from an interfacial surfacebetween the first conductive type semiconductor layer 110 and thesubstrate 101 due to the difference in a thermal expansion coefficientbetween the two materials, and a second stress P2 is generated from aninterfacial surface between the first conductive type semiconductorlayer 110 and the absorption layer 105 due to the difference in athermal expansion coefficient between the two materials. Accordingly,the first conductive type semiconductor layer 110 reacts with anadjacent material such that the first stress P1 is offset from thesecond stress P2. Accordingly, stress caused by the thermal expansioncoefficient difference from an adjacent material can be reduced.

The substrate 101 may include sapphire having a thermal expansioncoefficient greater than that of a group III-V compound semiconductor(e.g., GaN). The absorption layers 105 may be spaced apart from eachother at a preset interval by using ZnO. The ZnO has a thermal expansioncoefficient of about 2.9×10⁻⁶/K, the sapphire has a thermal expansioncoefficient of about 7×10⁻⁶/K, and the GaN has a thermal expansioncoefficient of about 5.6×10⁻⁶/K, but the above thermal expansioncoefficients may have various values.

Since the stress between the substrate 101 and a compound semiconductorsuch as the first conductive type semiconductor layer 110 is offset fromthe stress between the absorption layer 105 and the first conductivetype semiconductor layer 110, the first conductive type semiconductorlayer 110 can prevent the substrate 101 from being bent due to thethermal expansion difference, prevent potential defects, orsignificantly reduce cracks. In addition, a crack-free nitridesemiconductor thin film can be grown.

The active layer 120 is formed on the first conductive typesemiconductor layer 110. The active layer 120 may have a single quantumwell structure, a multiple quantum well structure, a quantum wirestructure, or a quantum dot structure. The active layer 120 may have astack structure including a well layer and a barrier layer, which aremade from compound semiconductors of group III-V elements. For example,the active layer 120 may have a stack structure of an InGaN welllayer/GaN barrier layer, an InGaN well layer/AlGaN barrier layer, or anInGaN well layer/InGaN barrier layer, but the embodiment is not limitedthereto. The band gap of the barrier layer may be higher than the bandgap of the well layer.

A conductive clad layer may be formed on and/or under the active layer120. The conductive clad layer may include a nitride-basedsemiconductor. The conductive clad layer may have band gap higher thanthat of the barrier layer.

The second conductive type semiconductor layer 130 is formed on theactive layer 120. The second conductive type semiconductor layer 130includes the group III-V compound semiconductor doped with the secondconductive dopant. For instance, the second conductive typesemiconductor layer 130 may include at least one selected from the groupconsisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP,GaAs, GaAsP, and AlGaInP. If the second conductive type semiconductorlayer is a P type semiconductor layer, the second conductive dopantincludes the P type dopant such as Mg or Ze. The second conductive typesemiconductor layer 130 can be prepared as a single layer or a multiplelayer, but the embodiment is not limited thereto.

The first conductive type semiconductor layer 110, the active layer 120,and the second conductive type semiconductor layer 130 may be defined asthe light emitting structure 135. In addition, the second conductivetype semiconductor layer 130 is provided thereon with the thirdconductive type semiconductor, for example, an N-type semiconductorhaving polarities opposite to those of a second conductive type. Thus,the light emitting structure 135 may include at least one of an N-Pjunction structure, a P-N junction structure, an N-P-N junctionstructure, and a P-N-P junction structure.

Referring to FIGS. 5 and 6, the protective layer 140 is formed on thesecond conductive type semiconductor layer 130, and formed at a channelregion corresponding to an individual chip boundary. The protectivelayer 140 is formed around the individual chip region by using a maskpattern. The protective layer 140 may have a continuous pattern or adiscontiuous pattern having a ring shape, a band shape, or a frameshape. The protective layer 140 may include a material (e.g., an oxide,a nitride, or a insulating material) having a refractive index lowerthan that of compound semiconductors of group III-V elements. Theprotective layer 140 may include one selected from the group consistingof ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, GZO, SiO₂, SiO_(x),SiO_(x)N_(y), Si₃N₄, Al₂O₃, and TiO₂. The protective layer 140 ispatterned by using a mask through a lithography process. The protectivelayer 140 may be formed through a sputtering scheme or a depositionscheme using the above materials. If the protective layer 140 is aconductive oxide, the protective layer 140 may serve as a currentdiffusion layer or a current injection layer.

Referring to FIGS. 6 and 7, the electrode layer 150 is formed on thesecond conductive type semiconductor layer 130. The electrode layer 150makes contact with the top surface of the second conductive typesemiconductor layer 130. The electrode layer 150 is formed on the secondconductive type semiconductor layer 130 to reduce contact resistance.

The electrode layer 150 may include at least one of an ohmic layer, areflective layer, and adhesion layer. The ohmic layer may be prepared inthe form of a layer or a plurality of patterns. The ohmic layer mayinclude at least one of a metallic material and an oxide material. Theohmic layer may include at least one selected from the group consistingof ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, GZO, IrOx, RuOx,RuOx/ITO, Ni/IrOx/Au, Ni/IrOx/Au/ITO, Pt, Ni, Au, Rh, and Pd. Thereflective layer may be prepared in the structure of at least one layerincluding Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and alloythereof. The electrode layer 150 may be deposited through an electronbeam (E-beam) scheme or may be formed through a sputtering scheme or aplating scheme, but the embodiment is not limited.

The electrode layer 150 may have a stack structure of a first adhesionlayer/electrode layer/second adhesion layer/seed layer. The first andsecond adhesion layers include Ni, the electrode layer includes Ag, andthe seed layer includes Cu. The first adhesion layer has a thickness ofa few nanometers (nm) or less, and the electrode layer has a thicknessof a few hundreds nanometers (nm). The second adhesion layer may have athickness of a few tens nanometers (nm), and the seed layer may have athickness of about 1 μm or less, but the embodiment is not limitedthereto.

The electrode layer 150 may completely cover the whole area of theprotective layer 140 or partially cover the protective layer 140. Sincethe electrode layer 150 includes reflective metal, the electrode layer150 may serve as an electrode. In addition, the electrode layer 150 andmetallic materials thereon may serve as an electrode.

The adhesion layer 160 is formed on the electrode layer 150. Theadhesion layer 160 includes barrier metal or bonding metal. For example,the adhesion layer 160 may include at least one selected from the groupconsisting of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag and Ta, but theembodiment is not limited thereto.

The adhesion layer 160 may serve as a bonding layer, and the top surfaceof the adhesion layer 160 is bonded with the conductive support member170. The conductive support member 170 serves as a base substrate. Theconductive support member 170 may include Cu, Au, Ni, Mo, Cu—W, or acarrier wafer such as Si, Ge, GaAs, ZnO, SiC, SiGe, or GaN. Theconductive support member 170 may be bonded with the adhesion layer 160,formed as a coating layer of the adhesion layer 160, or attached to theadhesion layer 160 in the form of a conductive sheet. According to theembodiment, the adhesion layer 160 may not be formed. In this case, theconductive support member 170 may be formed on the electrode layer 150.

Referring to FIGS. 8 to 10, the conductive support member 170 is placedon the base substrate, and the substrate 101 is provided on the lightemitting structure 135. Therefore, the substrate 101 is removed.

The substrate 101 may be removed through a laser lift off (LLO) process.According to the LLO process, a laser beam having a predeterminedwavelength band (e.g., 248 nm, 193 nm) is irradiated into the substrate101 to separate the substrate 101. The laser beam having the wavelengthpasses through the substrate 101 having a band gap higher than laserenergy, and is absorbed into a layer (e.g., the absorption layer 105)and the first conductive type semiconductor layer 110 having a band gaplower than the laser energy. In this case, the substrate 101 can beseparated from the absorption layer 105 and the first conductive typesemiconductor layer 110 because the interfacial surface of the substrate101 is removed relative to the absorption layer 105 and the firstconductive type semiconductor layer 110.

Referring to FIGS. 8 and 9, laser shots are given onto the substrate101. The laser shots are sequentially given in a scan direction SD inthe unit of one shot. In this case, one side x1 of one shot may havevarious lengths, but the embodiment is not limited thereto. Adjacentlaser shots overlap with each other on the absorption layer 105. Anoverlap region D2 has a width of about 5 μm to 10 μm. The overlap regionD2 may have a width narrower than or equal to that of the absorptionlayer 105. The overlap region D2 may be arranged in the absorption layer105 (e.g., a thickness of about 10 μm to 30 μm).

The absorption layer 105 is provided corresponding to the overlap regionD2 of the laser shots to absorb a laser beam in the overlap region ofedges of the laser shots, so that the semiconductor layers 110, 120, and130 can be prevented from being damaged.

As shown in FIG. 10, as the laser beam is sequentially irradiated ontothe substrate 101, the regions of the substrate 101 receiving the laserbeam are sequentially separated. The portion of the substrate 101 ontowhich the laser beam has been irradiated is separated, and a portion ofthe absorption layer 105 onto which the laser beam is not irradiated hasa crack C1 due to the separation of the substrate 101. The crack C1exists in the absorption layer 105, and is not delivered to anothersemiconductor layer. Accordingly, when the substrate 101 is separated, acrack can be prevented from occurring on the surface of the firstconductive type semiconductor layer 110.

As shown in FIG. 11, if the substrate 101 is removed, the top surface ofthe first conductive type semiconductor layer 110 and the absorptionlayer 105 is exposed.

Referring to FIGS. 11 to 13, the light emitting structure 135 of thechannel region M1, which is a boundary region between chips, is removedthrough an isolation etching process. In other words, the isolationetching process is performed with respect to the boundary region betweenchips, so that a portion of the protective layer 140 is exposed in thechannel region M1, and the lateral surface of the light emittingstructure 135 may be inclined or vertically formed due to the isolationetching process.

A portion or an entire portion of the absorption layer 105 may beremoved, and the absorption layer 105 becomes the stepped structure 104.The portion or the entire portion of the stepped structure 104 may beremoved through a wet etching process. The process of removing theabsorption layer 105 may be performed before or after the isolationetching process is performed. The wet etching process may be performedby using etchant selectively including HNO₃, CH₃COOH, H₃PO₄, or H₂SO₄,but the embodiment is not limited thereto.

Through the isolation etching process, an upper portion of the steppedstructure 104 may be open, or the step region 104 may have the shape ofcontinuous grooves formed along the edge of the first conductive typesemiconductor layer 110.

The protective layer 140 transmits the laser beam to prevent lower metalmaterials such as the electrode layer 150, the adhesion layer 160, andthe conductive support member 170 from protruding in the irradiationdirection of the laser beam or from being broken. In addition, theprotective layer 140 may protect the outer wall of each layer of thelight emitting structure 135.

An etching process is performed with respect to the first top surface S1of the first conductive type semiconductor layer 110 such that roughnessor a pattern may be formed on the top surface. The roughness or thepattern may improve light extraction efficiency. The insulating layer180 may be formed around the light emitting structure 135. Theinsulating layer 180 may be formed on the first top surface S1 of thefirst conductive type semiconductor layer 110 and at the lateral surfaceof the layers 110, 120, and 130 of the light emitting structure 135. Inaddition, the insulating layer 180 may extend to the top surface of theprotective layer 140. The insulating layer 180 may include a material,such as SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃, or TiO₂, having arefractive index lower than the refractive index (GaN: about 2.4) of thecompound semiconductor. The insulating layer 180 and the protectivelayer 140 may prevent moisture from being permeated into the chip.

The second top surface S2 lower than the first top surface S1 isprovided in the stepped structure 104 of the first conductive typesemiconductor layer 110, and the insulating layer 180 is formed in astepped shape at the stepped structure 104 including the second topsurface S2. The stepped structure 104 may improve light extractionefficiency or light orientation distribution.

The electrode 115 may be formed on the first conductive typesemiconductor layer 110 or at another region of the first conductivetype semiconductor layer 110, and may be electrically connected to thefirst conductive type semiconductor layer 110. The electrode 115 mayinclude a branch-type pattern and pad having a predetermined shape.

An individual chip unit is formed based on a chip boundary. Theindividual chip unit may be formed through a cutting process, or a laseror breaking process, but the embodiment is not limited thereto. Theinner part of the top surface of the protective layer 140 makes contactwith the outer portion of the lower surface of the second conductivetype semiconductor layer 130.

When the top surface of the first conductive type semiconductor layer110 is subject to polishing or lapping, the stepped structure 104 may beremoved, and the material of the absorption layer 105 may exist.

FIG. 14 is a side sectional view showing a light emitting device 100Aaccording to a second embodiment. Hereinafter, the second embodimentwill be described while focusing on the difference from the firstembodiment in order to redundancy.

Referring to FIG. 14, the light emitting device 100A includes a steppedstructure 104A having a loop shape formed on the first conductive typesemiconductor layer 110. The stepped structure 104A having the loopshape is formed by the second top surface S2 lower than the first topsurface S1 within the first top surface S1. The stepped structure 104Amay have a recess shape or a concave shape with an open top surface. Thestepped structure 104A has a first recess portion between a firstlateral surface of the first conductive type semiconductor layer 110 andthe electrode 115, a second recess portion between a second lateralsurface of the first conductive type semiconductor layer 110 and theelectrode 115, and plurality of third recess portions connected to thefirst recess portion and the second recess portion.

The stepped structure 104A is provided inside an upper portion of thefirst conductive type semiconductor layer 110, and the interval betweenthe stepped structures 104A may be an interval between two shots of thelaser beam. For example, the interval between the stepped structures104A is a distance from the first recess portion to the second recessportion of the stepped structure 104A. The interval between the twoshots of the laser beam may be determined differently from the channelregion M1, which is subject to the isolation etching, according to achip size. For example, if a chip having a large area is required, thestepped structure 104A corresponding to the interval between two shotsof the laser beam may be aligned inward as compared with a chip edge.

The insulating layer 180 may be provided around the light emittingstructure 135. The insulating layer 180 may prevent moisture from beingpermeated from the outside of the light emitting structure 135. Thestepped structure 104A may not be covered by the insulating layer 180.

The electrode layer 150 may extend outwardly from a lower portion of thelight emitting structure 135, and the insulating layer 180 may extend tothe top surface of the electrode layer 150 in the channel region.

A current blocking layer 137 may be formed between the electrode layer150 and the second conductive type semiconductor layer 130, and thecurrent blocking layer 137 may overlap with the electrode 115 in athickness direction of the light emitting structure 135. The currentblocking layer 137 may include at least one selected from the groupconsisting of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, ZnO, SiO₂,SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃, and TiO₂. When the electrode layer150 includes Ag, the current blocking layer 137 may include ITO, ZnO, orSiO₂. A single-layer pattern, a multiple-layer pattern, or a layer,which includes one selected from the group consisting of ITO, IZO, IZTO,IAZO, IGZO, IGTO, AZO, ATO, ZnO, SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄,Al₂O₃, TiO₂, Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, andselective combination thereof, may be interposed between the electrodelayer 150 and the second conductive type semiconductor layer 130, butthe embodiment is not limited thereto.

FIG. 15 is a side sectional view showing a light emitting device 100Baccording to a third embodiment. The third embodiment will be describedwhile focusing on the difference between the third embodiment and thefirst and second embodiments in order to avoid redundancy.

Referring to FIG. 15, in the light emitting device 100B, an interval T2between the protective layers 140 is different from an interval T1 ofthe stepped structures 104A.

The protective layer 140 may be provided in the form of a close loopbetween the second conductive type semiconductor layer 130 and theelectrode layer 150, and may be provided in a single layer structure ora multiple layer structure. The interval T2 between the outer sides ofthe protective layer 140 may serve as one chip interval.

The stepped structure 104A having a height lower than that of the firsttop surface S1 is formed inside the first top surface S1 of the firstconductive type semiconductor layer 110. The interval T1 between thestepped structures 104A may be less than the interval T2 between theprotective layers 140.

The interval T2 of the protective layer 140 is formed through anisolation etching process, and the interval T1 of the stepped structures104A is formed through a laser lift process. Accordingly, when theinterval T2 of the protective layers 140 is greater than the interval T1of the stepped structures 104A according to a chip size, the stepregions 104A may be provided inward from the edge of the firstconductive type semiconductor layer 110.

The insulating layer 182 is formed around the light emitting structure135. One side of the insulating layer 182 is formed on the protectivelayer 140, and an opposite side of the insulating layer 180 extends tothe first top surface S1 of the first conductive type semiconductorlayer 110. The protective layer 140 may be provided on a top surfaceand/or a lower surface thereof with a roughness or a pattern, but theembodiment is not limited thereto.

FIGS. 16 and 17 are side sectional views showing a method ofmanufacturing a light emitting device according to a fourth embodiment.Hereinafter, the fourth embodiment will be described while focusing on adifference between the above embodiments and the fourth embodiment inorder to avoid redundancy.

Referring to FIGS. 16 and 17, an absorption layer 106 is formed on thesubstrate 101, and a capping layer 107 is formed on the absorption layer106. The absorption layer 106 may include a metallic oxide, such as ZnO,WO, or MoO, having a band gap lower than that of a nitride semiconductoror the substrate 101.

The capping layer 107 may include Al₂O₃, AlN, TiN, or CrN. The cappinglayer 107 covers a top surface of the absorption layer 106, and servesas a buffer used to grow a compound semiconductor.

The capping layer 107 may include a material, such as Al₂O₃ or AlN,having a lattice constant difference less than that of the absorptionlayer 106, or a material, such as TiN or CrN, capable of improving anadhesive strength with a compound semiconductor.

The absorption layer 106 absorbs a laser beam irradiated in an LLOprocess to separate the substrate 101. The capping layer 107 may solve aproblem in which a compound semiconductor is not grown sufficiently dueto the material of the absorbing layer 106. According to the embodiment,although a stack structure of the absorption layer 106 and the cappinglayer 107 has been suggested, a transmissive layer may be provided underthe absorption layer 106 or the capping layer 107. The transmissivelayer may include one selected from the group consisting of SiO₂ andAl₂O₃, or one selected from the group consisting of ITO, IZO, IZTO,IAZO, IGZO, IGTO, AZO, and ATO. The capping layer 107 and/or thetransmissive layer can reduce the damage caused when the substrate 101is separated.

After the substrate 101 has been subject to the LLO process, thesubstrate 101 is removed, and the absorption layer 106 and the cappinglayer 107 are removed through a wet etching process. An isolationetching process and a chip separating process are performed tomanufacture a device shown in FIG. 17. In this case, the capping layer107 and/or the absorption layer 106 may exist in the step region 104 ofthe first conductive type semiconductor layer 110 of the finalsemiconductor device, but the embodiment is not limited thereto.

FIGS. 18 and 19 are side sectional views showing a method ofmanufacturing a light emitting device according to a fifth embodiment.Hereinafter, the fifth embodiment will be described while focusing onthe difference between the above embodiments and the fifth embodiment inorder to avoid redundancy.

Referring to FIGS. 18 and 19, absorption layers 108 are formed on thesubstrate 101 at a laser shot interval, and a capping layer 109 isprovided to cover an internal lateral surface an a top surface of theabsorption layer 108. The absorption layer 108 may be provided on thesubstrate 101 or on the transmissive layer, and the capping layer 109may be provided at the lateral surface and the top surface of theabsorption layer 108 to surround the absorption layer 108.

In an individual chip, the absorption layer 108 and the capping layer109 may be provided on edges of the first conductive type semiconductorlayer 110 or provided inward from the edges of the first conductive typesemiconductor layer 110, but the embodiment is not limited thereto.

After the substrate 101 has been subject to the LLO process, thesubstrate 101 is removed, and the absorption layer 108 and the cappinglayer 109 are removed through a wet etching process. An isolationetching process and a chip separating process are performed tomanufacture a device shown in FIG. 19. In this case, the capping layer109 and/or the absorption layer 108 may exist in the step region 104 ofthe first conductive type semiconductor layer 110 of the finalsemiconductor device, but the embodiment is not limited thereto.

A roughness or a pattern 132 may be formed on the first top surface S1of the first conductive type semiconductor layer 110, or a flat surfacemay be formed under the electrode 115, but the embodiment is not limitedthereto.

FIG. 20 is a sectional view showing a light emitting device package 30according to a tenth embodiment.

Referring to FIG. 20, the light emitting device package 30 according tothe embodiment includes a body 10, first and second lead electrodelayers 31 and 32 formed on the body 10, the light emitting device 100provided on the body 10 and electrically connected to the first andsecond electrode layers 31 and 32 and a molding member 40 that surroundsthe light emitting device 100.

The body 20 may include a conductive substrate including silicon,synthetic resin including PPA, a ceramic substrate, an insulatingsubstrate, or a metallic substrate (e.g., MCPCB). An inclined surfacemay be formed around the light emitting device 100. The body 20 mayinclude a through hole structure, but the embodiment is not limitedthereto.

The first and second lead electrodes 31 and 32 are electricallyinsulated from each other and supply power to the light emitting device100. The first and second lead electrodes 31 and 32 may reflect lightemitted from the light emitting device 100 to increase light efficiency,and may discharge heat emitted from the light emitting device 100 to theoutside.

The light emitting device 100 may be mounted on the body 20 or on thefirst and second lead electrodes 31 and 32.

The light emitting device 100 may be electrically connected with thefirst lead electrode 31 through a wire, and may be connected with thesecond lead electrode 32 through a die bonding scheme.

The molding member 40 may protect the light emitting device 100 whilesurrounding the light emitting device 100. In addition, the moldingmember 40 may include phosphors to change the wavelength of lightemitted from the light emitting device 100. A lens may be provided onthe molding member 40, and the lens may be realized in a contactstructure or a non-contact structure with the molding member 40.

The light emitting device 100 may be electrically connected with thebody 20 or a lower surface of a substrate via a through hole.

At least one of the above light emitting devices according to theembodiments may be mounted is the light emitting package, but theembodiment is not limited thereto.

Although the embodiment has been described in that the light emittingdevice package has a top view type, the light emitting device packagemay have a side view type. Accordingly, a heat sink characteristic,conductivity, and a reflectance characteristic can be improved. Aftersuch a top-view-type or side-view-type light emitting device is packagedin the resin layer, a lens may be formed on the resin layer or the lensmay be bonded with the resin layer, but the embodiment is not limitedthereto.

<Lighting System>

The light emitting devices and the light emitting device packagesaccording to the embodiments may be applied to a light unit. The lightunit may have an array structure including a plurality of light emittingdevices or a plurality of light emitting device packages. The lightingsystem may include a display apparatus shown in FIGS. 21 and 22, a lightunit shown in FIG. 23, in addition to a lighting lamp, a signal light, avehicle headlight, an electronic display, etc.

FIG. 21 is a disassembled perspective view of a display apparatusaccording to an embodiment.

Referring to FIG. 21, the display apparatus 1000 according to theembodiment may include a light guide panel 1041, a light emitting module1031 supplying light to the light guide panel 1041, a reflective member1022 under the light guide panel 1041, an optical sheet 1051 on thelight guide panel 1041, a display panel 1061 on the optical sheet 1051,and a bottom cover 1011 receiving the light guide panel 1041, the lightemitting module 1031, and the reflective member 1022, but the presentdisclosure is not limited thereto.

The bottom cover 1011, the reflective sheet 1022, the light guide panel1041, and the optical sheet may be defined as a light unit 1041.

The light guide panel 1041 functions to transform linear light to planarlight by diffusing the linear light. The light guide panel 1041 may bemade of a transparent material, and may include one of acryl-seriesresin such as polymethyl metaacrylate (PMMA), polyethylene terephthlate(PET), poly carbonate (PC), COC, and polyethylene naphthalate resin.

The light emitting module 1031 provides light to at least a side surfaceof the light guide panel 1041, and finally acts as a light source of adisplay apparatus.

The light emitting module 1031 may include at least one light emittingmodule, and provide light directly or indirectly from one side surfaceof the light guide panel 1041. The light emitting module 1031 mayinclude a board 1033, and a light emitting device package 30 accordingto embodiments disclosed above, and the light emitting device packages30 may be arranged apart by a predetermined interval from each other onthe board 1033.

The board 1033 may be a printed circuit board (PCB) including a circuitpattern (not shown). The board 1033 may include a metal core PCB(MCPCB), a flexible PCB (FPCB), etc. as well as the general PCB, but thepresent disclosure is not limited thereto. In the case where the lightemitting device package 30 is mounted on a side surface or a heatreleasing plate, the board 1033 may be removed. Herein, some of the heatreleasing plate may contact an upper surface of the bottom cover 1011.

The plurality of light emitting device packages 30 may be mounted on theboard 1033 such that light emitting surfaces of the plurality of lightemitting device packages 30 are spaced apart by a predetermined distancefrom the light guide panel 1041, but the present disclosure is notlimited thereto. The light emitting device package 30 may supply lightto a light incident part that is one side surface of the light guidepanel 1041, directly or indirectly, but the present disclosure is notlimited thereto.

The reflective member 1022 may be provided under the light guide panel1041. The reflective member 1022 reflects light incident from a lowersurface of the light guide panel 1041 to allow the reflected light to bedirected toward an upper direction, thereby capable of enhancingbrightness of the light unit 1050. The reflective member 1022 may beformed of, for example, PET, PC, PVC resin, or the like, but the presentdisclosure is not limited thereto.

The bottom cover 1011 may receive the light guide panel 1041, the lightemitting module 1031, the reflective member 1022, and the like. For thispurpose, the bottom cover 1011 may have a receiving part 1012 formed ina box shape a top surface of which is opened, but the present disclosureis not limited thereto. The bottom cover 1011 may be coupled to a topcover, but the present disclosure is not limited thereto.

The bottom cover 1011 may be formed of a metal material or resinmaterial, and may be manufactured by using a process such as a pressmolding or an injection molding. Also, the bottom cover 1011 may includemetallic or nonmetallic material having a high thermal conductivity, butthe present disclosure is not limited thereto.

The display panel 1061 is, for example, an LCD panel, and includes firstand second transparent substrates facing each other, and a liquidcrystal layer interposed between the first and second substrates. Apolarizing plate may be attached on at least one surface of the displaypanel 1061, but the present disclosure is not limited thereto. Thedisplay panel 1061 displays information by using light passing throughthe optical sheet 1051. The display apparatus 1000 may be applied to avariety of mobile terminals, monitors for notebook computers, monitorsfor lap-top computers, televisions, etc.

The optical sheet 1051 is disposed between the display panel 1061 andthe light guide panel 1041, and includes at least one transparent sheet.The optical sheet 1051 may include, for example, at least one of adiffusion sheet, a horizontal and/or vertical prism sheet, and abrightness reinforcing sheet. The diffusion sheet diffuses incidentlight, the horizontal and/or vertical prism sheet focuses incident lighton a display region, and the brightness reinforcing sheet enhances thebrightness by reusing lost light. Also, a protective sheet may bedisposed on the display panel 1061, but the present disclosure is notlimited thereto. Herein, the display apparatus 1000 may include thelight guide panel 1041, and the optical sheet 1051 as optical memberspositioned on a light path of the light emitting module 1031, but thepresent disclosure is not limited thereto.

FIG. 22 is a cross-sectional view of a display apparatus according to anembodiment.

Referring to FIG. 22, the display apparatus 1100 includes a bottom cover1152, a board 1120 on which the light emitting device packages 30disclosed above are arrayed, an optical member 1154, and a display panel1155.

The board 1120 and the light emitting device package 30 may be definedas a light emitting module 1060. The bottom cover 1152, the at least onelight emitting module 1060, and the optical member 154 may be defined asa light unit.

The bottom cover 1152 may be provided with a receiving part, but thepresent disclosure is not limited thereto.

Herein, the optical member 1154 may include at least one of a lens, alight guide panel, a diffusion sheet, a horizontal and vertical prismsheet, and a brightness reinforcing sheet. The light guide panel may beformed of polycarbonate (PC) or poly methyl methacrylate (PMMA), and maybe removed. The diffusion sheet diffuses incident light, the horizontaland vertical prism sheet focuses incident light on a display region, andthe brightness reinforcing sheet enhances the brightness by reusing lostlight.

The optical member 1154 is disposed on the light emitting module 1060.The optical member 154 transforms light emitted from the light emittingmodule 1060 to planar light, and performs diffusion, light focusing, andthe like.

FIG. 23 is a perspective view of a lighting unit according to anembodiment.

Referring to FIG. 23, the lighting unit 1500 may include a case 1510, alight emitting module 1530 equipped in the case 1510, and a connectionterminal 1520 equipped in the case 1510 and supplied with an electricpower from an external power supply.

The case 1510 may be preferably formed of a material having good heatshielding characteristics, for example, a metal material or a resinmaterial.

The light emitting module 1530 may include a board 1532, and at leastone light emitting device package 30 according to the embodimentsmounted on the board 1532. The light emitting device package 30 mayinclude a plurality of light emitting device packages which are arrayedapart by a predetermined distance from one another in a matrixconfiguration.

The board 1532 may be an insulator substrate on which a circuit patternis printed, and may include, for example, a printed circuit board (PCB),a metal core PCB, a flexible PCB, a ceramic PCB, an FR-4 substrate, etc.

Also, the board 1532 may be formed of a material to efficiently reflectlight, and a surface thereof may be formed in a color capable ofefficiently reflecting light, for example, white color, or silver color.

The at least one light emitting device packages 30 may be mounted on theboard 1532. Each of the light emitting device packages 30 may include atleast one light emitting diode (LED) chip. The LED chip may include acolor LED emitting red, green, blue or white light, and a UV LEDemitting ultraviolet (UV).

The light emitting module 1530 may have a combination of various lightemitting device packages so as to obtain desired color and luminance.For example, the light emitting module 1530 may have a combination of awhite LED, a red LED, and a green LED so as to obtain a high colorrendering index (CRI).

The connection terminal 1520 may be electrically connected to the lightemitting module 1530 to supply power. The connection terminal 1520 maybe screwed and coupled to an external power in a socket type, but thepresent disclosure is not limited thereto. For example, the connectionterminal 1520 may be made in a pin type and inserted into an externalpower, or may be connected to the external power through a power line.

According to the embodiment, as described above, after the lightemitting device 100 has been packaged, the package may be provided onthe substrate to realize a light emitting module. According to theembodiment, after the light emitting device shown in FIG. 1 has beenprovided on the substrate 101, the light emitting device may be packagedto realize the light emitting module.

The method of manufacturing the light emitting device according to theembodiment includes a step of forming an absorption layer formed on asubstrate, including a material having a band gap lower than a band gapof the substrate, and having a loop shape having a first interval; astep of forming a plurality of compound semiconductor layers including afirst conductive type semiconductor layer, an active layer, and a secondconductive type semiconductor layer; a step of forming a transmissiveprotective layer at an outer peripheral portion of the compoundsemiconductor layers; a step of forming an electrode layer on thecompound semiconductor layers; a step of irradiating a laser beam ontothe substrate at a laser shot size of the first interval to separate thesubstrate; a step of removing the absorption layer; and a step offorming a first electrode electrically connected with the firstconductive type semiconductor layer.

According to the embodiment, the damage of the semiconductor layeraccording to the removal of the substrate can be prevented, and thereliability for the light emitting device can be improved.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A light emitting device comprising: a light emitting structureincluding a first conductive type semiconductor layer, a secondconductive type semiconductor layer, and an active layer between thefirst conductive type semiconductor layer and the second conductive typesemiconductor layer, wherein the first conductive type semiconductorlayer includes a stepped structure having a second top surface steppedlower than the first top surface thereof; an insulating layer disposedon a lateral surface of the light emitting structure and the second topsurface of the first conductive type semiconductor layer; an electrodeelectrically connected with the first conductive type semiconductorlayer and disposed on at least one of the first and second top surfacesof the first conductive type semiconductor layer; an electrode layerunder the second conductive type semiconductor layer; a protective layerdisposed on a periphery portion of a bottom surface of the secondconductive type semiconductor layer and having an open region on thebottom surface of the second conductive type semiconductor layer; anadhesion layer under the electrode layer; and a conductive supportmember under the adhesion layer, wherein the protective layer is formedof a different material from a material of the insulating layer, andwherein the protective layer includes an inner portion between thebottom surface of the second conductive type semiconductor layer and theelectrode layer and an outer portion extending outward from a bottomsurface of the light emitting structure.
 2. The light emitting device ofclaim 1, wherein the stepped structure is disposed to an edge portion ofthe first conductive type semiconductor layer, and wherein theconductive support member has a width wider than that of the bottomsurface of the light emitting structure.
 3. The light emitting device ofclaim 1, wherein the second top surface has a depth of about 100Å toabout 30000Å from the first top surface of the first conductive typesemiconductor layer, and wherein the first conductive type semiconductorlayer includes an n-type dopant and the second conductive typesemiconductor layer includes a p-type dopant.
 4. The light emittingdevice of claim 1, further comprising metallic oxide layer or a metallicnitride layer between the second top surface of the first conductivetype semiconductor layer and the insulating layer.
 5. The light emittingdevice of claim 1, wherein the stepped structure of the first conductivetype semiconductor layer has a continuous loop shape, and wherein thesecond top surface of the first conductive type semiconductor layer isdisposed to be closer to an edge portion of the first conductive typesemiconductor layer than a center portion of the first conductive typesemiconductor layer.
 6. The light emitting device of claim 2, wherein aninterval between both second top surfaces of the first conductive typesemiconductor layer is less than an interval between a first region anda second region of the inner portion of the protective layer, andwherein the first region and the second region of the inner portion aredisposed under both sides of the second conductive type semiconductorlayer.
 7. The light emitting device of claim 1, wherein the protectivelayer includes at least one selected from the group consisting of indiumtin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO),indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO),indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tinoxide (ATO), gallium zinc oxide (GZO), SiO₂, SiO_(x), SiO_(x)N_(y),Si₃N₄, Al₂O₃, and TiO₂, and is formed in a single layer structure or amultiple layer structure.
 8. The light emitting device of claim 1,wherein the electrode layer includes an ohmic layer and a reflectivelayer, and wherein at least one of the ohmic layer and the reflectivelayer is physically contacted with the bottom surface of the secondconductive type semiconductor layer.
 9. The light emitting device ofclaim 1, wherein the electrode layer partially covers a lower portion ofthe protective layer or fully covers the lower portion of the protectivelayer.
 10. The light emitting device of claim 1, further comprising acurrent blocking layer interposed between the second conductive typesemiconductor layer and the electrode layer, wherein the electrode isdisposed on the first conductive type semiconductor layer, and thecurrent blocking layer overlaps with the electrode in a thicknessdirection of the light emitting structure.
 11. The light emitting deviceof claim 1, wherein the electrode is disposed on the first top surfaceof the first conductive type semiconductor layer and is spaced apartfrom the stepped structure.
 12. The light emitting device of claim 2,wherein the second top surface has a horizontal plane with respect tothe lateral surface of the light emitting structure.
 13. The lightemitting device of claim 12, wherein the second top surface of the firstconductive type semiconductor layer has a continuous loop shapeaccording to the edge portion of the first conductive type semiconductorlayer.
 14. The light emitting device of claim 12, wherein a thicknessbetween the second top surface and a bottom surface of the firstconductive type semiconductor layer is thinner than a thickness betweenthe first top surface and the bottom surface of the first conductivetype semiconductor layer.
 15. The light emitting device of claim 13,wherein the inner portion of the protective layer is physicallycontacted with the bottom surface of the second conductive typesemiconductor layer and overlaps with the second top surface of thefirst conductive type semiconductor layer in a thickness direction ofthe light emitting structure.
 16. A light emitting device packagecomprising: a body; a plurality of lead electrodes on the body; a lightemitting device provided on at least one of the lead electrodes, andelectrically connected with the lead electrodes; and a molding member onthe light emitting device, wherein the light emitting device comprises:a light emitting structure including a first conductive typesemiconductor layer, a second conductive type semiconductor layer, andan active layer between the first conductive type semiconductor layerand the second conductive type semiconductor layer, wherein the firstconductive type semiconductor layer includes a stepped structure havinga second top surface stepped lower than the first top surface thereof;an insulating layer disposed on a lateral surface of the light emittingstructure and the second top surface of the first conductive typesemiconductor layer; an electrode electrically connected with the firstconductive type semiconductor layer and disposed on at least one of thefirst and second top surfaces of the first conductive type semiconductorlayer; an electrode layer under the second conductive type semiconductorlayer; and a protective layer disposed on a periphery portion of abottom surface of the second conductive type semiconductor layer, anadhesion layer under the electrode layer; and a conductive supportmember under the adhesion layer, wherein the protective layer is formedof a different material from a material of the insulating layer, andwherein the protective layer includes an inner portion between thebottom surface of the second conductive type semiconductor layer and theelectrode layer and an outer portion extending outward from a bottomsurface of the light emitting structure.
 17. The light emitting deviceof claim 11, wherein the first top surface has a flat surface.
 18. Thelight emitting device of claim 11, wherein the first top surface has aroughness.
 19. A light emitting device comprising: a light emittingstructure including a first conductive type semiconductor layer, asecond conductive type semiconductor layer, and an active layer betweenthe first conductive type semiconductor layer and the second conductivetype semiconductor layer, wherein the first conductive typesemiconductor layer includes a stepped structure having a second topsurface stepped lower than the first top surface thereof; an insulatinglayer disposed on a lateral surface of the light emitting structure andthe second top surface of the first conductive type semiconductor layer;an electrode disposed on the first top surface of the first conductivetype semiconductor layer; a protective layer including an inner portiondisposed under a periphery portion of a bottom surface of the secondconductive type semiconductor layer; and an electrode layer including areflective layer under the second conductive type semiconductor layerand the protective layer; wherein the stepped structure is disposed toan edge portion of the first conductive type semiconductor layer and thesecond top surface has a horizontal plane with respect to the lateralsurface of the light emitting structure, and wherein the protectivelayer is formed of a different material from a material of the secondconductive type semiconductor layer and is physically contacted with theinsulation layer, an adhesion layer under the electrode layer; and aconductive support member under the adhesion layer, wherein theprotective layer is formed of a different material from a material ofthe insulating layer, wherein the inner portion of the protective layeris disposed between the bottom surface of the second conductive typesemiconductor layer and the electrode layer, and wherein an outerportion of the protective layer is extended outward from a bottomsurface of the light emitting structure.
 20. The light emitting deviceof claim 19, wherein the inner portion of the protective layer isphysically contacted with the bottom surface of the second conductivetype semiconductor layer and overlaps with the second top surface of thefirst conductive type semiconductor layer in a thickness direction ofthe light emitting structure.